====== Check List before contacting the GAMS support ======
In case you think GAMS or the solver fails, please provide us with as much relevant information as possible, such as:
    * Your operating system 
    * GAMS version and solver used
    * Size and structure (linear, nonlinear etc.) of the model 
Most of these information are included in the **log file** (.log): 
  * If you are using the GAMSIDE, there will be a file called ''model_name.log'' in your GAMS project directory. 	Alternatively you may just copy and paste the content of the process window into an e-mail.
  * If you are working from the command line, please use the additional  command line option lo=2 (e.g. ''gams trnsport.gms o=2'') to redirect the screen output into a log file. 

Find below an example of a log file (''trnsport.log''):
<code>
--- Job trnsport.gms Start 05/16/08 14:58:33
GAMS Rev 227  Copyright (C) 1987-2008 GAMS Development. All rights reserved
Licensee: Franz Nelissen                                 S080428/0001CN-WIN
          GAMS Software GmbH                                         DC3459
--- Starting compilation
--- trnsport.gms(69) 3 Mb
--- Starting execution: elapsed 0:00:00.004
--- trnsport.gms(45) 4 Mb
--- Generating LP model transport
--- trnsport.gms(66) 4 Mb
---   6 rows  7 columns  19 non-zeroes
--- Executing CPLEX: elapsed 0:00:00.009

ILOG CPLEX       May  1, 2008 22.7.2 WIN 4792.4799 VIS x86/MS Windows
Cplex 11.0.1, GAMS Link 34 

Reading data...
...
</code>
Please send us that file. 

If possible also attach a (zipped) copy of your model and all necessary data files, which will allow us to reproduce the problem. If there are include files or other data sources, please use the ''dumpopt'' parameter to produce a single source file. In case there are confidential issues, you may send us a scalar version of your model,  [[conversion_of_confidential_models_for_submission_to_gams_support|click here]] for instructions about that and the usage of the ''dumpopt'' option.

Our e-mail system can handle attachments up to a size of 15MB. If you have to send us larger files we recommend to use a free exchange file service provider. We have made good experiences with [[http://drop.io/#|drop.io]].

As a security measure to prevent potential viruses, our mail system does not accept executable files (such as files ending in .exe, bat, or cmd), even if they are sent in a zipped (.zip, .tar, .tgz, .taz, .z, .gz) format. Any message of this type sent to us will be bounced back you. Adding an underscore to the file attachment (e.g. file.zip_) will help.

Please also visit our [[http://support.gams-software.com/|Support Wiki]].

You can reach GAMS by several means of communication: mail, fax and phone. The full addresses are:
  - GAMS Development Corporation, 1217 Potomac Street, NW, Washington, DC 20007, USA
    * Phone: 	(+1) 202 342-0180
    * Fax: 	(+1) 202 342-0181
    * [[support@gams.com|support@gams.com]] 
   - GAMS Software GmbH, Eupener Str. 135-137, 50933 Cologne, Germany
     * Phone: 	(+49) 221 949-9170
     * Fax: 	(+49) 221 949-9171
    * [[support@gams.com|support@gams.com]] or [[info@gams.de|info@gams.de]]